spreadsheet showing why M8 and FF have same DOF

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ampguy said:
I'm very passionate about dispelling bull-shett.
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Don't get me wrong - if you're happy with your pictures when following the DOF scale on the lens, so much the better.

But if you insist on being passionate about dispelling something, dispel the pictures in the first page of the thread then. There you have it in a nutshell. The maths is clear, so are the pictures. Same with your cameras, except somewhat less obvious, which is why Leica can write about it the way they do. News at 11.
 
ampguy said:
One of the questions I asked was same camera on tripod, same lens, focus, f-stop, but image 1 is FF film, image 2 is a smaller piece of film, say 27x18mm, develop and print them both, cutting off the excess overscan of image 1 to equal image 2 FOV.

Is the DOF the same? Some adamantly said no.
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Again, you leave the most important question open, which is: are the resulting prints, the cut-off print of full-frame image 1 with the full-frame print of cropped image 2, supposed to be the same size?

If so, DOF is the same, because it doesn't matter if you crop in camera or in printing as long as the final FOV and print size is the same. This is very obvious if you actually try the exercise, because you will find that you can leave your enlarger at the same setting while doing it.

If not, the exercise is somewhat pointless, because DOF comparisons across prints of different size make different assumptions about circles of confusion.

Try it one day and see for yourself. Don't do indoor shots at f/8, though, because you won't see anything.
 
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ampguy said:
according to DOF Master online, the LX3 should give about 6 cm total DOF, while the 5D should give about 30 cm total DOF, assuming focus is at 1m, and would be even less at a shorter focal point.

Sure looks like the LX3 has a little more DOF, doesn't it?
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You didn't use the calculator correctly. You forgot to switch to 5.1mm focal length for the LX3.

Unless you want to pretend the LX3 has a 24mm lens - then your fov is different.
 
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I go to bed in the normal world, England scrape through the qualifiers, but only to lose to Germany on penalties in the next round ... and when I get up it's gone all weird again, all poor science and dogma, and this dawn of the dead thread is back to haunt us ...
 
DOF is subjective and scene-content driven.

Photographs of an 18% greyscale card filling the frame can be enlarged to any scale using any lens on any format camera and have the same DOF.

That is so deep. Deep Depth. I amaze myself.

Edit- just to add, the lens' image circle does not even need to fill the frame.

Really Deep, Baby.
 
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Brian Sweeney said:
DOF is subjective and scene-content driven.

Photographs of an 18% greyscale card filling the frame can be enlarged to any scale using any lens on any format camera and have the same DOF.

That is so deep. Deep Depth. I amaze myself.

Edit- just to add, the lens' image circle does not even need to fill the frame.

Really Deep, Baby.
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agreed- the often cited definition of DOF : depth of field (DOF) is the portion of a scene that appears acceptably sharp in the image. My understanding is that, historically the standard enlargement was an 8x10 print viewed at arms length. It's subjective and the DOF markings are a guideline. I guess gear heads and fondlers find this unacceptable.
 
monochromejrnl said:
... I guess gear heads and fondlers find this unacceptable.
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I think the concept of bokey figures into it as well. Back in the day, we would just deal with the background by either moving, or occasionally opening up to make it blurry. Now-a-days the quality of that blurriness is as important, or more so, than the subject of the photo.

Prints, especially 8x10s are becoming passe. Photos are viewed on computer screens and the ability to magnify them to monstrous proportions is commonly used. This has given rise to the calculability of DoF as a quasi-absolute quantity.

I find that I am in a minority of photo-enthusiasts who prefer to look at prints. And sometimes they are not 8x10, nor at arm's length.
 
Consider two photos of exactly the same scene printed to the same size at the same aperture. The first photographed on a mobile phone, the second on a 10x8 large format camera.

I think we would all agree that the DOF of the former will be greater than the latter. In addition I think that we would agree that the rate of change of the DOF will be progressive between the two formats, that being the case, then the DOF of the m8 must be greater than a full frame camera.
 
So it seems, in order not to confuse their customers, Leica have decided to thoroughly confuse them. Good thing they don't provide even smaller formats for their M-lenses...

ampguy is right, of course. But he is not answering the original question.

Such a sad thread. And we would need no higher math and no specialist papers to resolve the issue... yawn...
 
ampguy said:
What Finder/Roland and others propose is even more radical than the Zeiss PDF which indicates 1 stop between APS-C and FF (the table in the PDF gives no data point for a ~32mm diag. sensor, which is a lot closer to their 40mm diag (which they use for FF, not 43.2?), than to their APS-C diag size (26mm).

Perhaps Finder and Roland may want to revise their estimate to an appropriate fraction?

I'm all ears here ...
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Making things up again. Actually, I proposed exactly the same thing as the Zeiss document. You just don't get it.
 
*sigh*

You know.. I've seen this conversation (exact same one) since the appearance of affordable DSLRs (if not before).

I honestly thought people "got it" by now....but I think everything travels slower in the Leicaverse.

Dave
 
The solution to this question is for all existing M8 users to sell their cameras to get the M9, which is obviously better, due to the smaller dof, hence driving down the prices of the M8 so much that poor people like me can finally get one. 😀
 
Chris101 said:
I think the concept of bokey figures into it as well. Back in the day, we would just deal with the background by either moving, or occasionally opening up to make it blurry. Now-a-days the quality of that blurriness is as important, or more so, than the subject of the photo.
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I was under the impression that this particular fad was already on the way out, to be replaced by HDI composites and by ultra high ISO impossible night shots.
 
I think next; I'm going to shoot a 360 degree panoramic, twist it into a mobius strip, pop it in an envelope and post it to Erich von Däniken.

Lets see if he has some answers to that
 
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